Age of sea floor rocks increases in symmetric pattern away from spreading centers and mid-ocean ridges.

Convergent

?Plates collide

?Subduction occurs

?Lithosphere is consumed

Convergent Boundries

?Oceanic-Continental

?Denser oceanic plate subducts

?Partial melting occurs

~100km depth

?Magma rises to

surface

Convergent Boundries Oceanic-Continental

?Oceanic-Continental

?Subduction of oceanic crust

produces continental

volcanic arcs

?Cascade Mountains

?Andes Mountains

Convergent Boundries Oceanic-Oceanic

?Oceanic-Oceanic

?Similar to

continental-oceanic

?Partial melting

?Produces volcanic

island arc

Convergent Boundries Continental-Continental

?Continental-Continental

?Both plates are bouyant

?Minimal/no

subduction

?Crust buckles and

rises or moves

sideways

orogensis. def.

?

?Orogenesis: mountain building

(Himalayas)

Transform boundries

?Lateral movement

?Common at right angles to

divergent boundaries

along mid-ocean ridges

?Few on land

most famous transform boundry

san andres fault, california

Plate tectonics...processes include

?Processes include

?Lithospheric plate movement

?Upwelling of magma

?Sea floor spreading

Plate subduction

?Earthquakes

?Volcanic activity

?Lithospheric deformation

Hot Spots

?Hot spots

A fixed point of upwelling magma

?Stationary mantle plume

?Lithospheric plates move over

?Can create a string of volcanic islands

Hawaiian hot spots

?Hawaiian Islands

chain

?Stationary plume

?Pacific plate shifts

?Youngest islands

are closest to the

active plume near

Hawai?i

?Older seamounts

further away

Volcanic Activity

?Three main locations

1.Along subduction boundaries

?Convergent boundaries

?Continental-oceanic, oceanic-oceanic

2.Along sea floor spreading centers

?Divergent boundaries

?Oceanic and continental

3.At hot spots

Earthquakes

A release of energy at the rupture along a fault

?Plates do not glide past one another

?Stress creates strain

?Builds until friction is overcome

?Release of enormous amounts of energy

Earthquake Tectonics

?Common along convergent boundaries

?Plate subduction

causes friction

?Helped plot plate

boundaries

State Mineral

State Mineral: Galena (Lead sulphide)

State Rock

State Rock: Red Granite Chosen for its economic importance in the state in 1971, the speckled igneous rock is composed of quartz and feldspar.

Wisconsin Dome

WI Dome is highest in center of state and rocks dip away to east and west

Cuestas

Cuestas form from erosion of the gently dipping bedrock

Cuestas have a steep slope, where the rock layers are exposed on their edges, called an escarpment or, if more steep, a cliff. Usually an erosion-resistant rock layer also has a more gentle slope on the other side of the ridge called a dip slope. The steeper slopes face inside anticlinals and outside eroded sinclinals.

The process by which rocks disintegrate, or dissolve, or are broken down

?Physical

?Frost action, crystallization, pressure release jointing

?Chemical

?Hydration, hydrolysis, oxidation, solution,

?Does NOT include transport

?Creates regolith

Partially weathered rock material overlying the bedrock

?Influences on weathering

?Joints

Fractures or separations

in a rock

?Increases surface area

?Climate

?Physical weathering common in drier, cooler regions

?Chemical weathering common in wetter, warmer regions

?Slope orientation

?Slope facing away from sun will be cooler, moister, more vegetated

?Vegetation

?May serve as protective cover and stabilize soil

?Release of acids

?Roots enter crevasses

?Time

physical weathering

?Breakdown of a rock with NO chemical alteration

?Produces more surface area

Frost Action

?Frost Action

?Water expands up to 9% when frozen

?Creates tension to break apart rocks

?Repetition of expanding and contracting

?Common in higher latitudes and altitudes

Freeze/thaw frees rocks, accumulates as a talus slope

Crystalization

?Crystallization

?Salt crystals form, enlarge and create force

?Breaks apart rocks grain by grain

?Common in arid climates

Physical weathering

?Pressure release jointing

?As overlying material is removed, pressure lessens

?Layers of rock ?peel? off

Hydrolisys

?Hydrolysis

?Minerals chemically combine with

water- causes silicate minerals in

rocks to break down

?Produces clays, silica

?Granular disintegration takes place first

Weaker minerals break down,

disrupting interlocking networks

?Then spheroidal weathering

Sharp edges/ corners become rounded

Oxidation

?Oxidation

?Metallic elements combine with oxygen to form oxides

??Rusting? of rocks and soils

?Can make rocks more

susceptible to further

weathering

Chemical Weathering-Solution

?Solution

?Minerals dissolve completely

?Produces dissolved compounds

?Commonly breaks

down limestones,

salts, even marble

Biochemical weathering

?Biochemical weathering

?Some organisms release chemicals that degrade rock surfaces

?Lichens

?Excrete acid

?Extract nutrients

?Chemically

degrade surface

Karst Landscape

A landscape (typically appears bumpy or pitted)formed by the dissolution of limestone